I've seen this problem on Just-Dice, and I know me and dooglus have thought of this as a solution at least once, but it still requires trust of the party that holds the server. It's an interesting solution, but I'm eager to see how it works out.
I have asked dooglus to check our code and eventually run the roll server, but i guess he is very busy with his own business at the moment.
lol...."Hey dooglus can you help us, a competitor of your site, test our site to see if it would be good enough to take some of the market share from you" is essentially what you're asking.